Sanders was invited to attend a conference hosted by the Pontifical Academy of Social Sciences "on social, economic, and environmental issues," according to a release from the Sanders campaign.
The trip abroad means that Sanders will be off the campaign trail in New York for a period of time before the state's hotly contested April 19 primary against Hillary Clinton. Sanders has been hoping to upset Clinton in her home state and his absence from the campaign trail in the final week of the battle for New York comes as a surprise.
The Democratic presidential candidate's appearance at the conference will coincide with the 25th anniversary of the "Centesimus Annus," an encyclical from Pope John Paul II that addresses workers' rights and other economic and social issues that are similar to those Sanders has stressed in his White House bid.
"I am delighted to have been invited by the Vatican to a meeting on restoring social justice and environmental sustainability to the world economy," Sanders said in the release.
"Pope Francis has made clear that we must overcome 'the globalization of indifference' in order to reduce economic inequalities, stop financial corruption and protect the natural environment. That is our challenge in the United States and in the world."
In an interview on MSNBC's "Morning Joe" Friday morning, Sanders praised the pope when he was asked about the invitation.
"I was very moved by the invitation, which just was made public today," he said. "I am a big, big fan of the pope. Obviously, there are areas where we disagree, on women's rights and gay rights. But he has played an unbelievable role -- an unbelievable role -- of injecting a moral consequence into the economy."
Sanders also joked about the pope's push to liberalize aspects of the Catholic Church, adding, "you know, people say Bernie Sanders is radical -- read what the pope is writing."
He did not say if he would be meeting with Pope Francis in his release.
The Pontifical Academy of Social Sciences also marked the upcoming trip in a statement, writing
, "We're delighted to host this conference to celebrate the 25th anniversary of Centesimus Annus, bringing together world leaders, including U.S. Senator Sanders."
Mons. Marcelo Sanchez Sorondo, chancellor of the academy, also discussed Sanders's scheduled visit in a phone call.
"It does not signify any support of the campaign," Sorondo explained. "We want to establish a dialogue between North America and South America so we thought to invite a (U.S.) politician. The President of Bolivia will also be there. Perhaps the others (candidates) would have been interested but they did not request to come."
Asked if Sanders had requested an invitation, he said, "He has expressed an interest many times in the Pope's encyclical and it's clear that he has an interest in studying it. It might have that effect, (of looking like they approve of campaign) but we are not looking to support the campaign."
Sorondo added that he did not know if Sanders would receive an audience with the pope.
Sanders' visit to the Vatican was announced the same day that Pope Francis released a sweeping paper
urging Catholic priests around the world to be more accepting of gay men and lesbians, divorced Catholics, and other people living in what the church considers "irregular" situations."
In the letter, the pope urges more common sense and less unthinking following of rules -- what he calls "discernment" -- and writes, "by thinking that everything is black and white, we sometimes close off the way of grace and growth."